An industrial association known as the digital living network alliance (DLNA) is promoting standardization activities for interconnecting electrical household appliances and personal computers from different manufacturers. According to a DLNA guideline defined by the DLNA, a function is provided in which a digital media player (DMP) acquires content data from a digital media server (DMS) connected thereto via a network, and allows for remote viewing of the content data. Further in the DLNA guideline, in accordance with instructions from a digital media controller (DMC), a digital media renderer (DMR) can also acquire content data from the digital media server (DMS) and allow for remote viewing of the content data. In the following description, the digital media renderer (DMR), the digital media server (DMS), and the digital media controller (DMC) are simply referred to as a content playback device, a server device, and a control device, respectively.
The following problems are possible in a system where the content playback device acquires content data from the server device and allows for remote viewing of the content, in accordance with the content playback instruction from the control device.
One problem is that when the content playback device playing a content item is given instructions from the control device to play another content item, the originally played content item is undesirably and unintentionally stopped. This case where content is originally played includes those wherein content data is acquired from the server device and the content data is remotely viewed, but also TV viewing using a TV tuner included in the content playback device, content playback by media player functionality which plays content stored in a SD card, a universal serial bus (USB) memory, a hard disk drive (HDD), a digital versatile disc (DVD), or a Blu-ray disc (BD), playback of external video input from outside such as game and a BD player, and use of various applications such as web site browsing using a browser.
For example, the following two use cases are possible in a system where the content playback device acquires content data from the server device and allows for remote viewing of the content data, in accordance with the content playback instruction from the control device.
A use case 1 is where a user operates the control device to select content, and issues the content playback instruction from the control device by manual operation at a time intended by the user to play the content. A use case 2 is where the control device automatically detects update of content in the server device on the Internet, at which time automatically issues the content playback instruction.
Each use case will be briefly described with reference to FIG. 1 and FIG. 2.
FIG. 1 is a diagram showing the configuration of the content playback system in the use case 1. Specifically, FIG. 1 is a diagram of a home network in which a control device A102, a content playback device 101, and a server device 103 are interconnected via a local area network (LAN) 104. A wired LAN (Ethernet (registered trademark)) or a wireless LAN (IEEE802.11) is often, but not exclusively, used for the LAN 104.
First, the user operates the control device A102 to acquire a listing of content in the server device 103, and selects content to be played. Next, the user uses the control device A102 to instruct the content playback device 101 to play the selected content. Thus, the content playback device 101 acquires content data to be played from the server device 103, and plays and displays the content data on a display unit (display) on the content playback device 101.
FIG. 2 is a diagram showing the configuration of the content playback system in the use case 2. Specifically, FIG. 2 is a diagram of a home network in which a control device B202 and the content playback device 101 are interconnected via the LAN 104. Here, it is assumed that the control device B202 connected to the Internet 205 via the LAN 104 can acquire various update information such as update information of news or weather forecast from the Internet 205, or update information of web sites on the Internet 205, and save corresponding content items (such as still images, videos, sounds) into a server function unit 203 in the control device B202.
A user can previously register, with the control device B202, pieces of information of interest among information to be updated on the Internet 205. Then, at a time when the registered information is updated, the control device B202 automatically gives the content playback instruction to the content playback device 101 to acquire and play content which corresponds to the updated information downloaded to the server function unit 203. Then, the user can view the content by seeing the display unit (display) on the content playback device 101.